Propeller-shaft support



C). MADER /n venzol: Jaw 772W Dac. 17 1929.

PROPELLER SHAFT SUPPORT Filed June 30. 1928 Patented Dea -1:7, 1929 UNITED sTAras Parana" FFICE orre MADER, or nnssau, sear/rear, assreivoa ro nuao rename, or :onssau,

' ennui/main PEOPELLER-SHAFT BUEEIEOR'I Appllcatlon fllecl June so, 191%, Serial no. status, and. in Germany July 1e, rear.

My invention relates to the supporting of propeller shaft-s, for instance the shafts of aircraft propellers. It is an object of my invention to provide a mode of supporting 5 such propellers, which permits a particularly efi'ective balancing of the propeller and 1ts shaft. To this end I support the propeller shaft at two points, its inner end being supported to permit the shaft to rock about a centre point 1n all directions, while the ropeller end of the shaft is supported resiliently in radial direction.

In high-speed propellers, such as are used in. aircraft, perfect balancing is very important in order to prevent straining and vibrating of the craft, or parts thereof, by unbalanced centrifugal forces. Effective balancin is particularly desirable in propellers which are not arranged in immediate vicinity of an engine block or other heavy unit, but are remote from such parts and operated through the medium of gears and shafting, only comparatively light and resilient parts, such as simple struts, being available as supporting means in the immediate vicinity of the ropeller. In this case the amplitude of vi rations due to unbalanced centrifugal forces is considerable. It is due to these vibrations which are not only troublesome but may even become dangerous, that the arrangement of the ropellers remote from the engines, which is esirable from an aerodynamic point of view, has not been adapted, or abandoned where it had been attempted.

'llhese drawbacks are overcome according to this invention in which the balancin of the ropeller is so perfect that the prope ler can be arran ed without difficulties at points where on y light and com aratively eresilient parts areavailable for t e support of its shaft. However, the advantages inherent in my invention are not limited to the case of propellers arranged at a point remote from the en ine for in the case ofa propeller arrange? in the immediate vicinity of an engine unit or other weighty mass the often very important'stresses on the propeller shaft due to unbalanced centrifugal forces and the load on their bearings are practically eliminated.

By arranging the propeller shaft bearings as described, the shaft is imparted the character of a free shaft. By this denomination is determined a shaft which, when rotating at high speed, automatically assumes a position in which its centre of gravity coinparts of aircraft is eliminated.

In the drawings affixed to this specification and forming part thereof shaft supports embodying my invention are illustrated diagrammatically by way of example.

In the drawings,

Fig. l is a partly sectional elevation and Fig. 2 is a section onthe line II-II in Fig. 1, illustrating the first modification, while Fig. 3 is an axial section on a larger scale,

showing a modified bearing for use in the vicinity of the propeller, and

Fi 4 is Fig.

Referring first to unit is indicated crank shaft crank shaft a section on the line IV--IV in Figs. 1 and 2, the engine diagrammatically by its 1, 2 is a pinion on the end of the 3 is a gear on a hollow shaft 9 meshing with pinion 2, 7 and 8 are bearings for the hollow shaft 9, 4 is the propeller shaft which is connected with the hollow shaft 9, by

clutch means 10, 11, and a universal joint 6,

having a stationary suport 6, and 5 is the propeller. Any suitable type of bearingmay be provided instead of the ball and socket joint shown,

at the inner end of the shaft for instance a ball thrust bearing with a spherical race, or any other typeof bearing I which possesses universal properties and is adapted to absorb the thrust of the propeller 5, and other means than the stud 6 may be provided as a thrust member.

The outer bearing of the shaft 4 is constituted by a which the shaft 4; is rotatably carried, and

two pairs casing 17, a bearing block 15 in of laminated springs 16 intermediate, the block and thecasing. The

sprin 's are he propeller shaft to adapt its position mit t to the unba comparatively Weak so as to peranced centrifugal forces and to A rotate about the axis containing the effective centre of gravity.

In operation the torque from the crank shaft 1 is transmitted to the shaft 4 through the medium of the gearing 2, 3, the clutch means 10, 11 andthe joint 6 without interfering with the rocking movement of the shaft which is free to assume any position about the centre of the joint 6 within practical limits, and the outer end of the shaft l is not interfered with by the springs 16.

Instead of laminated springs as shown any other resilient means as coiled springs, rubber blocks or the like, might be provided for supporting the outer bearing 15, and damping means might also be arranged for absorbing the shaking vibrations occurring when the propeller is started or running down. Laminated springs comprising several layers as shown at 16 involve the advantage of effecting such damping without requiring any special means therefor. All plates of laminated springs may be of equal. length and have duplicate supports at all points of abutment so as to enable the springs to absorb forces acting in either direction, making them twice as efficient as normal springs having bla des of graduated length.

The springs may also consist of bundles of comparatively thin bars or Wires of equal length as shown inFigs. 3 and 4. Referring to these figures, identical parts are indicated by the same reference numerals as in Figs. 1 and 2. 21 is a circular extension or disc formed on the outer bearing 15, 22 being bundles of wires, resilient bars or the like inserted in holes of the disc 21, 25 being a casing surrounding the shaft f at a suitable clearance, and 23, 242 being recesses in the end walls of the casing 25 for the reception of the bundles 22. The recesses 23,24 secure the bundles so as to prevent the wires or bars from changing their relative position in the bundle radially but permit slight relative axial displacement. The holes in the disc 21 are preferably beveled at their outer ends so that the bundles 22 are engaged substantially only in the central plane of the bearing 15. Springs of this type are able to absorb forces in any direction so that all springs will partake in the absorption of centrifugal forces when the shaft 4: is displaced from its normal position. The material of the springs is consequently utilized to best advantage and their weight is reduced in proportion.

Instead of a reduction gearing 2, 3 as shown, the propeller shaft 4 might be connected with the crank shaft 1 directlyv through the medium of a universal joint, for instance a Cardan joint, not shown, and intermediate shafts, not shown, might be pro vided between the shaftd and its driving means, such intermediate shafting being supported in rigid bearings and connected with 1,74dsea connected with said shaft by said universal coupling and resilient means supporting the propeller end of said. shaft for yielding radial motion in all directions.

2. Propeller shaft support comprising a shaft, a propeller at one, a universal coupling at the other end of said shaft, driving means connected with said shaft by said universal coupling and resilient means supporting the propeller end of said shaft for ielding radial motion in all directions about t e centre point of said coupling.

3. Propeller shaft support comprising a shaft, a propeller on the outer end of said shaft, driving means near the inner end of said shaft, a universal coupling connecting said shaft and driving means,a casing surrounding the outer end of said shaft, a hearing in said casing supporting said shaft and spaced from the inner walls of said casing, resilient means interposed between said bean ing and said casing to hold said bearing substantially in the centre of said casing and means near the inner end of said shaft for imparting rotation thereto.

l. Propeller shaft support comprising a shaft, a propeller on the outer end of said shaft, a bearing near the inner end of said shaft, driving means near the inner end of said shaft, a universal coupling operatively connecting said shaft with said driving means and permitting said shaft to rock in all directions about a centre point, a bearing near the outer end of said shaft, a casing surrounding said outer bearing and springs in-= serted between said outer bearing and said casing, and normally holding said bearing substantially in the centre of said casing, but permitting radial displacement bf said bearing in all directions.

5. Propeller shaft support comprising a propeller shaft, a propeller on the outer end of said propeller shaft, a bearing near the inner end of sa1d propeller shaft, a hollow driving shaft supported in said bearing, coupling means in said driving shaft, the inner end of said propeller shaft extending into said driving shaft and being operatively connected with said coupling means, means for centering said inner end 1n said driving shaft, while allowing said propeller shaft to rock aboutv said centering means, a bearing near the outer end of sa1d shaft, a casing surrounding said outer bearing and sprmgs inserted befilth llti tween said outer bearin and said casing and normally holding said %earing substantially in the centre of said casing, but permittinfi radial displacement of said bearing in a directions,

6. Propeller shaft support comprising a shaft, a ropeller on the outer end oi said shaft, a caring" near the inner end of said shaft, driving means near the inner end of w said shaft, a universal coupling at said inner end operatively connected with said driving means and permitting said shaft to rock in all directions about the centre point of said coupling, a resiliently mounted bearing near the outer end of said shaft arranged to permit radial displacement of said shaft'in all directions and damping means forming part of said resilientl mounted bearing.

'2'. Propeller shaft support comprising a shaft, a propeller on the outer end of said shaft, a caring near the inner end of said shaft, driving means near said inner end of said shaft, a universal coupling at said inner end operatively connected with said driving means and permitting said shaft to rock in all directions about the centre point of said coupling, a hearing near the outer end of said shaft, a casing surrounding said outer hearing, springs each comprisin a plurality of resilient bars of substantial y equal length inserted hetween said outer bearing and sai casing and normally holding said bearing substantially in the centre of said casing, but permittin radial displacement of said bear- 5 ing in all irections, and means near the inner end of said shaft for imparting rotation thereto.

in testimony whereof I afix my si 'ature.

OTTO Fl ER. 

